Luminous display or reflector sign



June 9, I931. J..c. STIMSON 1,809,761

LUMINOUS DISPLAY 0R REFLECTOR SIGN Filed July '9, 1925 3 Sheets-Shae; l

June 9, 1931. J. c. ASTIMSON 1,809,761

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Patented June 9, 1931 UNITED STATES JONATHAN c. srmson,

LUMINOUS DISPLAY Application filed July 9,

embodthe luminous display sign embodying this invention;

Figure dis a perspective view of a prismatic plate used in the display sign;

Figures 7, 8 and 9 show difierent applications of the reflector or prismatic plate in the formation of display characters on the luminous display or reflector sign embodying this invention;

Figs. 10, 11 and 12 are plan Views, showing a group of triple reflector units and characters superimposed thereon.

Display signs as heretofore made are of two general types, namely those in which the light is radiated from lamps formingthe display characters of the sign, and those in which the characters are displayed by diffuse reflection from the surfaces of the character on the si area.

Where the light is radiated directly from the lamps forming the characters, only a small part ofthe total emitted light is useful. This will be readily understood by reference to Figures 4 and 5, which illustrate a typical display sign installation em: bodying a sign 1 provided with electric lamp bulbs 2 forming the characters. The sign is..-

shown as mounted on the top of a low building 3 facing a main thorou hfare or street 4 and flanked by higher buil ings 5 and 6 facing on a cross street 7. It will be readily seen that the total light useful for display surfaces is that included within the spherical sector having a zone 8, 9, 10, 11. While the sign may be visible on thestreet 7 if placed on the front of the building 3, it will not be effective for the reason that a charactenis only readily legible when viewed within an a. masseuse angle deviatin approximately fifty degrees or less rom the perpendicular to the only a small percentage of the total emitted light from a bulb or a series of bulbs is utilized for display purposes, keeping in mind that. the light from a bulb is radiated in a sphere of which the source forms the center and that the useful light for display purposes forms only a small sector of the sphere. Accordingly since the intensity of the illugnination varies inversely as the square of the distance, it necessarily follows that in order to obtain a practical range of visibilit bulbs of relatively high candle power must e used. Not only is a display sign employing bulbs for direct radiation wasteful in energy, but the maintenance cost in the replacement of bulbs and repairs generally is also high, especially since in order to secure a display of given characters, these characters must be built up by a series of lights requiring a multiplicity of bulbs. Moreover, such characters being built up by spaced oint sources of light can only approximate t e outline ot the character, and require high power lamps sign. Accordingly it will be readily seen that v to make them visible at a distance. Suchsigns are, moreover, very expensive ,to install and operate. T

In luminous display signs in which the sign area is painted or formed to provide display characters which are illuminated by directing light from a suitable source or .sources onto the sign. area, the characters are visible by difi'use reflection. Such reflection fills the entire hemisphere in front of the sign although serving a useful purpose within only a small zone.

By reason of the nature ofthe surface of such a sign a large part of";

the light is absorbed, even when the sign is painted with ordinary paint. In order to avoid high lights, flat paints are sometimes used'resulting in a matte surface. From such a surface the light is even more fully diffused and there is a greater absorption of light. As a result the sign, in proportion to the amount of illumination used is effectively visible at short distances only. Fur-' ther, even at short distances such signs lack the brilliance of electric signs.

a selected field from which the displa characters are visible; this is accomplishe in the illustrated embodiments of this invention by reflecting the light from the display characters in the form of a spreading beam or beams into that selected, visible field.

Another object of this invention is to provide a luminous display or reflector sign having display characters visible from within a selected field, whereby the light emitted from the characters is confined within that field; this is accomplished in the illustrated embodiments of this invention by providing the characters with reflecting surfaces which are constructed and arranged to reflect the light impinging thereon in the form of a spreadving beam or beams and into that selected visible field in order to display the characters within that field.

Further objects will appear from the detail description taken in connection with the accompanying drawings.

Generally stated and in accordance with this invention the luminous display or refleeting sign has a sign character or characters provided with or formed of reflecting units arranged to form the outline or outlines of the-character or characters, each of these units has a reflecting area adapted to reflect li 'ht incident thereon from a distant source back in the general direction of the light source, and the units have means or are constructed to slightly spread the reflected light. The reflecting units are usually arranged along the strokes of the character to outline the same. These units maybe arranged in clusters along the character in accordance with an illustrative embodiment of this invention in which the reflecting surfaces forming the characters of the luminous display or reflector sign are in the form of tri le reflectors constructed as shown and descrlbed in Patent No. 1,671,- 086, issued May 22, 1928. A triple reflector comprises three reflecting surfaces arranged to intersect at a common point and such a reflector has the property of reflecting incident 'beams back to their source irrespective (within limits) of the angle of incidence of such a beam w1th respect to the axis. \Vhere the triple reflector'is a prism causing reflec-- tion of the incident beam, the limiting angle to luminous'display or reflector signs can be varied to suit requirements.

of incidence (with respect to the axis) can be increased while the loss of reflected rays is decreased for any given angle of incidence. While, however, in a central reflector (in which the reflecting surfaces are at ri ht angles-to each other so as to form in e ect the corner of a cube and which is provided with optically plane surfaces) the incident beams are reflected directly back to the source, the triple reflector described and shown in the patent referred to is so constructed as to reflect the impinging light in the form of a spreading beam or beams. This is accomplished in an embodiment of the invention described in the patent referred to, by deviating the reflecting surfaces thereof slightly from true right angular relation and by distorting the surfaces so as to vary from the true optical surface of a central reflector; specifically stated this latter is accomplished in a prismatic reflector by forming the reflector of pressed glass and by so controlling the degree of polish of the refleeting surfaces as to leave the same sufliciently rough and undulating to secure spread reflection. This is illustrated in Figures 6 and 7, where the surfaces of the triple reflector 12 are shown undulating (on an exaggerated scale) so that an incident beam 13 from a source of light 1 1 provided with a reflector 15 (such as a arabolic reflector) is reflected in the form 0 a spreading beam 16 which is of uniform intensity, the spread of thebeam being controlled by the degree of polish given the reflecting surfaces.

As a practical illustrative embodiment a reflecting area is formed by a prismatic plate 17 of pressed glass, which has formed on the back thereof a series of triple reflecting prisms 18 arranged in contiguous relation, the reflecting surfaces of these prisms being formed by pressing in a suitable mold and the polish of the reflecting surfaces being controlled by, the degree of polish given the mold surfaces. Such a prismatic plate has the property of reflecting incident substan;

tially parallel beams of light back past the source in the form of a cone having the plate as the apex of the cone and the source of light in the axis of the cone, regardless of the position of the light source with respect to the reflector within wide angular limits. If the reflecting plate is transparent, reflection takes place through total internal reflection, the angular range through which the transparent total triple reflecting prisms function being sufficient for most display signs. If service conditions require an angular range and quantit of reflection beyond the reflecting range 0 the transparent prismatic plate, the back or figured face of the plate may be silvered, thus widening the range through which all of the units'of the reflector will function.

The application of the reflecting prism in Figure 7 the characters 19 may be formed of pressed glass having formed on the back thereof a series of triple reflecting prisms whose reflecting surfaces are formed as heretofore described. These characters may Thus as shown either be used integrally or may be built up of parts, and such characters, or the parts thereof may besecured to a sign area in any suitable manner, it being understood, of course, that these prisms will project from the rear part of the character.

As shown in Figures 10 and 11 the sign area 20 or 21 may be formed of a prismatic plate, either in a single piece or built up from a series of plates, with the reflecting surfaces formed as heretofore described and with the triple reflecting prisms on the back of the sign area; The characters 22 or 23 may then be formed either by coating the sign area, leaving the outlines of the characters exposed as shown in Figure 10 or by coating the characters leaving the back-ground exposed as shown in Figure 11; in the first case, Figure 10, the characters will appear illuminated while in the second case Figure 11, the background will appear illuminated. It will'be understood, of course, that any suitable opaque paint or other coating may be used and this coating may even be translucent and in varyin colors so as to present a varied color disp ay. It will, of course, be understood that the total sign area need not be formed as a reflecting surface in either case but only such portions as are required. With this form of sum area the display charactersv may be varied y removal of the coating and by the application of anew coating.

Fi res 1 and 2 show the application of this invention to a location similar to that. shown in Figures 4 and 5, similar parts being indicated by similar characters. The frame of the sign 1 is provided with asign area 24, which is constructed in any'manner as heretofore described while the light is directed on the sign area and the display characters thereon from a suitable source, such as one or more lamp bulbs and a reflector 25 which is arranged to project the light on the sign area and the display characters. Any suitable reflector of a high concentrating type, such as a parabolic reflector or a re cently developed compensating Mangan mirror may be provided. Such a spot-light is so constructed and arranged as to throw a spreading beam in order to just cover, the sign area and the display characters thereon. From the principles of the reflector as heretofore described, it will bereadily seen that the light will be reflected from the display characters in the form of aspreading beam W or beams-and into the selected field (which is, in this case, along the street or thoroughfare 4), which field is that from which the luminous display is visible. It will be understood, of course, that the source of light and the impinging reflector 25 and the sign area are so relatively positioned and with respect to the visible field, and that the s read of the beam is controlledas heretofore escribed,

as to confine the reflected. light within the .power and a reflector of a suflicient size will be small relative to the sign area so that the sign area and the characters thereon will not be obscured by the presence of the source within the reflected beam; as a practical proposition the light projecting reflector 25 will really be invisible at a comparatively short distance from the sign area.

Occasionally a sign is favorably located in a position where it may be viewed without obstruction over a large territory. Such a location may be secured on the top of a high building facing an open public square or at the intersection of wide avenues forming an acute angle. Such a location, is shown in Figure 3' where the frame of the sign 1 containing the sign area 24 constructed as heretofore described is located on top of a building 26., In order to secure a distributed field, two or more spot-lights 27 and 28 are located to face the sign area, as by mounting the same on buildings 29 and 30 respectively. The

32, while the beam 33 from the spot-light 28 is reflected in the form of a spreading beam 34. The elements may be so constructed and relatively arrangedas heretofore described,

that the light will be reflected from the dis-' play characters in the form of spreading beams into the selected visible field, the light from the display characters and incident from the several sources being reflected into selected adjacent visible field areas so as to confine the-light reflected from the sign area and the display characters thereon within the visible field. By thus suitably arranginga series of spot-lights and by suitably constructing the sign areaand the reflecting surfaces, any desired field of vision may be covered, but the light emanating from the character is confined within that field.

It will, therefore, be seen that the invention accomplishes its objects, for in accordance with this invention the light emitted from the sign area and the display characters thereon is limited and confined within the visible field. Accordingly the emitted light is transmitted where it will be observable, while it is excluded from outside spaces. It will, therefore, be seen that maximum efficiency is secured even with the losses incident to the employment of reflectors and refractors. Not only is the cost of installation low, but the maintenance cost is low for the reason that the sign area is rugged and will not deteriorate. Nor will the efliciency be impaired on account of the ex osure to weather for the reason that the re ecting surfaces are in the rear where they can be protected. Where silvered plates are employed the reflectors may be sealed to the sign board or similarly treated so as to protect them from the weather. If transparent total reflecting plates are used little protection is necessary. It is to be noted in this connection that dust particles, if not in optical contact with the reflecting surfaces, will not impair the reflection but optical contact can readly be avoided by protecting the back against rain. The display sign is so constructed that any suitable-characters in the form of letters, figures, illustrations and trade marks may be employed without resorting to block characters. Moreover any suitable color effect may be obtained as heretofore described by suitable coating applied to the sign area. A desired color effect may also besecured by introducing a color screen in the path of the beam from the spot-light or by passing a varied color screen therethrough. Elaborate flashing effects may also be secured by simply moving an opaque screen'in the path of the beam from the spot-light, or by moving one containing perforations designed to securethe desired eflect, or by using a semi-trans parent screen containing gradations of shading. Furthermore the sign area may be converted and changed readily as heretofore described without great expense.

While a number of embodiments of this invention have been described and illustrated in an illustrative environment, it will be understood that this invention is susceptible of various embodiments and in various environments in the general art of reflecting signs to perform their useful functions in those environments. It is further obvious that various changes may be made in details without departing from the spirit of this invention; it is, therefore, to be understood that this invention is not to be limited to the specific details shown and described.

Having thus described the invention, what is claimed is:

1. A luminous display sign comprising, a reflecting area on which characters are displayed so as to be visible in front of said area, and a light source in front of and distant from said area adapted to direct the light on said area for reflection within a selected field, said reflecting area being com posed of reflecting surfaces formed and positioned to cause a definite spread of the reflected light from said area and so as to con fine the reflection within the selected field, in

order that the characters may be visible to an observer anywhere within that field.

2. A luminous display sign comprising, a reflecting area on which characters are displayed so as to be visible in front of said area, and a light source in front of and distant from said area adapted to direct the light on said area for reflection within a selected field, said reflecting area being composed of a series of reflecting units arranged in contiguous relation and constructed and positioned to cause a definite spread of the reflected light therefrom and so as to confine the reflect-ion within the selected field, in order that the characters may be visible to an observer anywhere within that field.

3. A luminous display sign comprising, a reflecting area on which characters are displayed so as to be visible in front of said area, and a light source in front of and distant from said area adapted to direct the light on said area for reflection within a selected field, said reflecting area being composed of a series or reflecting units arranged in contiguous relation, each of said units being constructed to direct a definite spreading beam of substantially uniform intensity into the selected field, and the composite beam from the several reflecting units being confined within the selected field, in order that thecharacters may be visible to an ob server anywhere within that field.

4. A luminous display sign comprising, a reflecting area on which characters are displayed so as to be visible in front of said area, and a light source in front of and distant from said area adapted to direct the light on said area for reflection within a selected field, said reflecting area being composed of a series of reflecting units arranged in contiguous relation, each of said units having reflecting surfaces constructed to direct a definite spreading beam into the selected field and having means for distributing the reflected light uniformly throughout the field of spread, and the composite beam from the several reflecting units being confined within the selected field, in order that the characters may be visible to an observer anywhere within that field.

5. A luminous display sign comprising, a reflecting area on which characters are displayed so as to be visible in front of said area, and a series of light sources in front of and distant from said area adapted to direct the light from said area for reflection within selected adjacent fields, said reflecting area being composed of reflecting surfaces formed and positioned to cause a definite spread of the reflected light from said area and so as to confine the reflection within the selected fields, in order that the characters may be visible to an observer anywhere within those fields.

6. A-luminous dis lay sign having display characters visible om within a selected field, and a light source in front of and distant from said characters, said characters having reflecting surfaces arranged in relative angular relation to multiply reflect light impinging thereon back towards the light source in the form of a spreading beam or beams, said reflecting means being adapted its to direct the reflected light into and confine the same to said field in order to display said characters within said field.

7. A luminous display sign having display characters visible from within a selected field, and a li ht source in front of and distant from sa1d characters, said characters being formed by total reflecting prisms whose surfaces are arranged in angular relation to multiply reflect the light in the form of spreading beams into and confined within the selected fleld.

8. A luminous displaysign having display characters visible from within a selected field, and a light source in front of and distant from said characters, said characters being formed by triple reflecting surfaces which deviate from their true right angular relation adapted to reflect the light into and within the selected field.

, 9. A luminous display sign having display characters visible from within a selected field, and a light source in front of and'distant from said characters, said characters being formed by triple reflecting surfaces adapted to reflect light impinging thereon back towards the light source, and means cooperating with sa1d surfaces adapted to slightly spread the reflected light to a definite degree in the form of a spreading beam or lpiezltns so as to confine the same within said 10. A luminous display sign having display characters visible from within a selected field, and means in front of and dis nt from s'aid'characters for directing light indiscriminately on said characters, said characters having triple reflectors whose reflecting surfaces-deviate from their true right angular relation adapted to reflect the light impinging thereon so as to confine the same within said field.

11. A luminous display sign having display characters visible from within a selected field, and means in front of and distant from said characters for directing light from a source on the display characters, said chara'cters being reflecting surfaces arranged in relative angular relation. to multiply reflect the light impinging on said display characters back towards said source, and means cooperating with said surfaces adapted to slightly spread the reflected light to a definite degree in the form of a spreading beam or beams into said field.

12. A reflecting sign having a sign character provided with reflecting units arranged to form an outline of the character, each of said units havingv a reflecting area adapted to reflect light incident thereon from a distant source backin the general direction of the light source and having means'adapted to shghtlg spread the reflected light.

13. reflecting sign having a sign character provided with reflecting units arranged this 7th day of July, 1923.

along the strokes of the character, each of tant source back in the general direction of the light source and having means adapted to slightly spread the reflected light.

.14. A reflecting sign having a sign character provided with clusters of reflecting units arranged to form an outline of the character, each of said units having a reflecting area adapted to reflect light incident thereon from a distant source back in the general direction of the light source and having means adapted to slightly spread the reflected light.

15. A reflecting sign having a sign character provided with clusters of reflecting units arranged to form an outline of the character, each cluster being composed of a series .of units arranged in contiguous relation, each of said units having a reflecting area adapted to reflect light incident thereon from a distant source back in the general direction of the light source and having means adapted to slightly spreadthe reflected light.

16. In a reflecting sign, the combination with a reflecting surface consisting of a number of prisms whose opposite sides meet at right angles at their apices, of means for blocking out portions of the reflecting surface to form a ,desi 1 17. In a re ecting sign, a single plate of glass having a reflecting surface consisting of a number of prisms whose opposite sides meet at right angles at their apices, and on its other surface means for blocking out portions to form a design.

18. In a reflecting sign, the combination with a reflecting surface consisting of a number of right angles tetrahe'dra, of means for blocking out portions of the surface to form a design. 7

19. In a reflecting sign, the combination with a reflecting surface consisting of a sheet of plate glass on which are formed a number of prisms whose opposite sides meet at right angles at their apices, of. means for blocking out portions of the-reflecting surface to form a design.

" 20. In a reflecting sign, the combination with a reflecting surface consisting of a sheet of plate glass on which are formed a number of right angled tetrahedra, of means for blocking out portions of the reflecting surface to form a design.

21. In a reflecting sign, a plate of glass having on one side thereof a plurality of tetrahedral prisms, and on its other side an opaque coating disposed to block out a sign substantially as and for the purpose I described.

' In testimony whereof I aflix my signature JONATHAN c. s'rrnson. 

